By all indications, Gary Doer very badly wants President Barack Obama to approve the Keystone pipeline. Doer, the Canadian ambassador to the U.S., simultaneously insists that if Obama refuses, Canada will sell its oil all the same. The missing word is "eventually," and opponents to the pipeline should take note.

Speaking at a Bloomberg Government breakfast yesterday, Doer argued that Alberta bitumen, a tar-like substance that can be refined into oil, will get to market regardless of whether Obama approves Keystone. Either it will be transported to the U.S. by truck and train, he said, or moved by pipeline to Canadian ports and shipped elsewhere in the world.

The ferocity of Canadian lobbying over Keystone belies that argument. So too does the unwillingness of British Columbia to support a pipeline carrying bitumen through its territory. Doer argued that new pipelines could be built to the Atlantic or Arctic oceans, but if those options were easy it's hard to see why he would devote so much of Canada's political capital to pushing a project that Obama supporters hate.

Even other Canadian officials acknowledge that blocking Keystone would affect development. Joe Oliver, Canada's minister for natural resources, said in April that trains were a poor alternative. "I don’t think anybody feels that it could be a substitute for pipelines," Oliver told Reuters, adding that shipping the oil by rail only would limit oil-sands production.

Canada's position that the pipeline is irrelevant to the future of the oil sands only makes sense as a rebuttal to environmentalists, some of whom claim that derailing the pipeline will stop further development. That argument is every bit as specious as the Canadian government's: No country in the world would leave that oil in the ground, environmental pretensions be damned. If the only goal that matters is to stop oil-sands development, Obama may as well approve Keystone tomorrow.

But Canada's assertion that its bitumen will be extracted, Keystone or no, underscores a better argument against the pipeline. Canada's contention is half-true: The oil sands will still be developed, but the question is how quickly. That question leads to the smarter environmental tactic: noting that the longer we wait to develop the oil sands, the less harm it might do to the climate.

Doer, probably unintentionally, backed up that point yesterday morning. "Every day we're improving our sustainability," he said. If that's true, then opposition to Keystone isn't just a matter of naivete and fuzzy thinking; it's also a delaying tactic that seeks to keep bitumen in the ground long enough for technology to diminish the environmental impact of its extraction.

Approving Keystone wouldn’t be "game over" for the climate, and the U.S. environmental movement could probably do just as much good by turning its attention to other pressing issues. But that doesn't mean there isn't a rational argument against the pipeline. Canada is probably right that the oil sands will be developed one way or the other -- eventually. Delaying that development is a worthwhile goal in itself.

(Christopher Flavelle is a member of the Bloomberg View editorial board. Follow him on Twitter.)